Machine for and method of finishing bushings



April 8, 1930. M. w iv s ET AL 1,753,632

MACHINE FOR AND METHOD OF FINISHING BUSHINGS Filed May 22, 1923 2 Sheets-Sheet 1 a i M" April 8, 1930. H. M. WILLIAMS ET AL MACHINE FOR AND METHOD OF FINISHING BUSHINGS Filed May 22, 1925 2 Sheets-Sheet 2 larflfnrs WHruasses Thain Patented Apr. 3, 1930 UNI-ran sT 'rEs j Emir it. wnmuns m cmam s L. -I.'r.'r.,'or niy'ron. onro, Assroirons 'ro GENERAL. coaromrron, or amon, 01:10, a coaroaarron or DELA- xoroas nasmncn was:

OFFICE momma roa AND warrior or rrmsmuo roan mos application filed Kay 22, 1923'. Serial No. 640,798.

metals capable of alloying when heated below the fusing point of at least one of them,with

a volatilizable substance, compressing a quan- -tity of the mixture thus formed into the contour of a bushin then heating the bushing blank thus forme in anon-oxidizing environment to such a temperature and for such a period that the particles of metal cohere or. sinter together and the volatilizable substance passes from the bushing blank leavmg 1t porous and susceptible of absorbing and retam- 'ing lubricants. In the practice of the described process it has been found that the bushings distort slightly or change their dimensions slightly during the heat treatment and hence it becomes important that the bushings be sized to the exact desired dimensions.

after the heat treatment. Also during the resizing of the bushings according to thls mvention the high pressure of the arbor and time upon the walls of the bushing give the bushing a Very smooth inner surface without reducin the porosity of said surface.

Further objects and advantages o f'the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 shows the essential parts of a machine for carrying out the method of this 111- vention, a bushing being shown in place ready to have thearbor inserted therethrou h.

Fig. 2shows a front elevation of t e stationary head for supporting the die, taken on the line 2-2 of Fig. 1'.

bushing 16 with die 15.

Fig. 3 is a plan View on line 3-3 of Fig. 1. V

Fig. 4 is a side elevation of the head, taken on line 44 of Fig. 3. Y I

' Fig. 5 is a rear elevation of the head and shows in dotted lines several positions ofthe bushings as they pass through slots provided in the head. Throughout the several viewsof the drawn'gs, similar reference characters refer to similar parts.

Numeral 10 designates the stationary base or bed plate. of the press whichsupports the bracket 11 to which thedie head 12 is rigidly secured by any suitable means such as by heavy bolts extending throughholes or slots inthe flanges. 13 '(see Fi s.2 and 5).

The sizing die *15' of suitably hardened steel is very rigidly secured in place, preferablyby a pressed fit, as clearly shown in Fig 1. -The' bushing 16 which is to be sized'is dropped into place-immediately in front of the die 15 through a suitable guide slot 17 and rests at the bottom of slot 17 upon a. V-

shaped support 18 so that it is aligned coaxially with the die 15. The reciprocating arbor 20 is co-axially aligned-with the die 15 and is provided at its tip with a reduced diameter portion 21 which is'readily inserted loosely through the bushing 16 and in this manner assists in guidin or-aligning the The portion 22 of arbor 20 is of slightly increased diameter and fits snugly but with suflicient clearance to prevent burnishing within the bushing 16 as the arbor 20 moves to the left, as viewed in, Fig. 1, until the. shoulder 23 of the arbor comes in contact with the edge of the bushing 16. However, before the portion .22 engages the bushing the enlarged portion 24 of the arbor 20 engages the .guide 25 rigidly fixed to the head 12, and the portion 21 of the arbor enmore accurately kept in absolute alignment with the die 15. After the shoulder 23 abuts the. edge of bushing 1 6 further movement of arbor 20 to the left presses the bushing 16 of the die-head, taken gages the guide 26 and thus the arbor 20 is elastic limit of the material of which the bushing is composed. Hence when the bushing 16 has been pressed entirely through the die into the open slot 30 the bushing will expand only a slight amount after the compressing pressure ,is removed. Thus .the diameter of the die 15 and of the portion22- of the arbor determine the dimensions of the finished bushing, and the degree of compression of the walls of the bushing is determined by the dimensions of the bushing before it has'been re-sized. The thickness of the walls of the bushing before re-sizi-ng'may be varied to vary the degree of compression to which the material of the bushing is subjected in the resizing operation. The high pressure exerted upon the inner surface of the bushing walls gives a very smooth surface which of course is highly advantageous when the bushing is to be used as abearing. Furthermore;

since there is no relative. sliding of the arbor 20 within thebushing during the application of the pressure the porosity of the inner surface of the bushing will not be decreased.

Special means have'been illustrated in the drawings for removing the bushing 16 from the arbor after it has passed through the die 15. For this purpose two spring pressed lugs 31 may be provided which extend laterally into the open slot 30, each lug 31 having a small beveled tip 32 which extends into the path of travel of bushing 16 as it'is pressed through the die 15. When the bushing 16 strikes the'beveled tips 32 the lugs 31 are pressed outward against the pressure of springs 33 to'permit the bushing 16 to pass between the beveled tips 32 which slide along the surface of the bushing. When the bushing has traveled far enough the tips 32 snap behind the edge of the bushing and then when the arbor 20 is withdrawn the bushing 16 is held from backward motion by the lugs 31. As soon as the arbor is clear of the bushing'16 it will fall out through the open slot 30as shown in dotted lines in Figs. 1 and 5. "The beveled tips 32 are preferably arc-shaped while the lugs 31 may be round and held from rotating by small projecting pins 34 which ride in the small grooves 35, as will be readily understood. The springs 33 are slightly compressed and held in place by the small cover plates 36 secured by thescrews 37 It has been found however, that the spring lugs 31 may be dispensed with simply by providing a sharp inner edge 40 on the exit end of the die 15. The slight expansion of the bushing on emerging from die 15 will prevent the bushing from reentering the die when the arbor is withdrawn to the right as seen in Fig. 1. Also the slight expansion of the, bushing will permit the easy withdrawal of the arbor from within the bushing.

While the machine illustrated in the drawings and described in detail herein may be used for carrying out the method of this in- I vention, other machines may be devised for carryin out this same method and it is not intended that the invention be limited in any, way other than by the scope of the appended clalms'.

What we claim is as follows:

1. A machine for sizing a compressible bushing, comprising in'combination, an arbor having a portion upon which the bushing fits; a female die member having an aperture through which the arbor and bushing may be moved, said aperture being of lesser transverse diameter than the outside diameter of the bushing, the entrance edge of said aperture being rounded; means for supporting thebushing is being moved through the female die member; and means for moving the erbor and its bushing through said die mem- 2. A machine for sizing -a compressible bushing, comprising in combination, an arbor providing three portions of varying diameters, the larger of which forms the main body of the arbor which is anchored to a movable member of the machine, the intermediate portion being smaller than the main body portion and upon which a bearing is adapted to fit so that its edge engages a shoulder formed between the body and intermediate portion, the third or free end portion beingstill smaller in diameter and providing a pilot for the arbor; a female die member having an aperture coaxial with the arbor for receiving the mandrel and its bushing, said aperture being slightly less in diameter than the outside diameter of the bushing and having a rounded entrance edge;

supporting and guiding collars rigidly secured on opposite sides of the female die member and spaced therefrom for receiving the pilot and body portion of the arbor, respectively, to hold them in axial alignment with the aperture of said female die member while the bushing is being moved therethrough; and means for moving the arbor.

3. A machine for sizing a compressible bushing comprising, in combination, an ar-' bor having a main supporting portion, a bushing receiving portion of smaller diameter than the main portion, thus providing a shoulder between said portions for engaging one end -of the bushing, and a guiding portion of smaller diameter than the bushing receiving portion for holding the bushing in substantial alignment with the sizin die during the first part of the movement 0 said arbor; means connected with the main su porting portion for moving the arbor; a emale die member through which bushing and arbor pass to compress the bushing around the arbor; and means for stripping the bushing from the arbor when the arbor is withdrawn from the die member.

4. A machine for sizing a compressible 80 I the arbor on each side of the bushing while bushing comprising, in. combination, an arbor having a mam supporting portion, a

bushing receiving portion of smaller diameter than the mam portion, thus roviding a shoulder between said portions or en ag-,

ing one end of the bushing, and a gui ng portion of smaller diameter than the bushing receiving portion for holdingthe bushing in substantial alignment with the sizing die during the first part of the movement of said arbor; means connected with the main supporting portion for moving the arbor; a female die member through which bushing and arbor pass to compress the bushing around the arbor; and a lug resiliently urged toward the arbor for en aging the end of the bushing adjacent the s oulder in order to strip the bushingfrom' the arbor.

5 The method ofsizing a bushing of porous metallic material to a desired predetermined size, which consists in inserting therethrough an arbor having a diameter equal to the desired inner diameter of the bushing,

then compressing the bushing on said arbor by passing the bushing through a die having the desired diameter while holding the bushing in fixed position relative to the arbor whereby burnishing of the inner surface of the bushing during the sizing operation is prevented.

6. The method of sizing a-bushingof porous metallic material to a desired predetermined size which consists in inserting therethrough an arbor having a diameter equal to the desired inner diameter of the bushing, then moving the arbor to force the bushin through a die having substantially the desired outside diameter of the bushing and supporting the arbor on each side of the bushing during its movement.

In testimony whereof we hereto aifix our signatures.

HARRY M. WILLIAMS. CHARLES L. LEE. 

